// Package service — NotificationService is the single seam every
// user-facing event flows through ("the notification plugin"). Today it
// does two things per event:
//
// 1. Persists a row in `notifications` (so an in-app notification center
// and, later, websocket + push delivery can read the same history).
// 2. Sends an email to the recipient via the shared mailer.
//
// Everything here is fire-and-forget from the caller's perspective: a
// follow request must succeed even if the email bounces or the insert
// fails, so Notify* never returns an error — failures are logged. When
// websocket/push land they hook in right here alongside the email send.
package service
import (
"bytes"
"context"
"html/template"
"strings"
"github.com/prabhupadasays/spsays-bff/internal/model"
"github.com/prabhupadasays/spsays-bff/internal/repository"
"github.com/prabhupadasays/spsays-bff/pkg/mailer"
"go.uber.org/zap"
)
// Notification kinds — short machine strings stored in notifications.kind.
const (
NotifFollowRequest = "follow_request"
NotifFollowAccepted = "follow_accepted"
)
type NotificationService struct {
notifs *repository.NotificationRepo
users *repository.UserRepo
mail mailer.Mailer
logger *zap.Logger
frontendURL string
}
func NewNotificationService(notifs *repository.NotificationRepo, users *repository.UserRepo, mail mailer.Mailer, logger *zap.Logger, frontendURL string) *NotificationService {
return &NotificationService{
notifs: notifs,
users: users,
mail: mail,
logger: logger,
frontendURL: strings.TrimRight(frontendURL, "/"),
}
}
// List returns the caller's notifications, newest first.
func (s *NotificationService) List(ctx context.Context, userID string, limit, offset int) ([]model.Notification, error) {
if limit <= 0 || limit > 100 {
limit = 30
}
if offset < 0 {
offset = 0
}
return s.notifs.ListByUser(ctx, userID, limit, offset)
}
// UnreadCount returns the caller's unread notification count (for the bell
// badge).
func (s *NotificationService) UnreadCount(ctx context.Context, userID string) (int, error) {
return s.notifs.CountUnread(ctx, userID)
}
// MarkAllRead marks all of the caller's notifications read.
func (s *NotificationService) MarkAllRead(ctx context.Context, userID string) error {
return s.notifs.MarkAllRead(ctx, userID)
}
// NotifyFollowRequest tells `recipientID` that `actorID` asked to follow
// them. Persists the row and emails the recipient (if they have an email
// on file).
func (s *NotificationService) NotifyFollowRequest(ctx context.Context, recipientID, actorID string) {
s.dispatch(ctx, recipientID, actorID, NotifFollowRequest,
"%s requested to follow you — Prabhupāda Says")
}
// NotifyFollowAccepted tells `recipientID` that `actorID` accepted their
// follow request (i.e. the recipient can now see actor's activity).
func (s *NotificationService) NotifyFollowAccepted(ctx context.Context, recipientID, actorID string) {
s.dispatch(ctx, recipientID, actorID, NotifFollowAccepted,
"%s accepted your follow request — Prabhupāda Says")
}
// dispatch persists the notification and sends the matching email. All
// failures are logged, never propagated.
func (s *NotificationService) dispatch(ctx context.Context, recipientID, actorID, kind, subjectFmt string) {
actor := actorID
if _, err := s.notifs.Create(ctx, recipientID, &actor, kind); err != nil {
s.logger.Warn("persist notification failed",
zap.String("recipient", recipientID), zap.String("kind", kind), zap.Error(err))
// Persistence failed, but still try to email — the email is the
// only delivery channel that exists today.
}
recipient, err := s.users.FindByID(ctx, recipientID)
if err != nil {
s.logger.Warn("notification recipient lookup failed", zap.String("recipient", recipientID), zap.Error(err))
return
}
if recipient.Email == nil || strings.TrimSpace(*recipient.Email) == "" {
// No email on file (OAuth-only account that never added one) —
// the persisted row is the notification; nothing to send.
return
}
actorUser, err := s.users.FindByID(ctx, actorID)
if err != nil {
s.logger.Warn("notification actor lookup failed", zap.String("actor", actorID), zap.Error(err))
return
}
body, err := s.render(kind, recipient, actorUser)
if err != nil {
s.logger.Warn("render notification email failed", zap.String("kind", kind), zap.Error(err))
return
}
subject := strings.Replace(subjectFmt, "%s", actorDisplay(actorUser), 1)
if err := s.mail.Send(strings.TrimSpace(*recipient.Email), subject, body); err != nil {
s.logger.Warn("notification email send failed",
zap.String("to", *recipient.Email), zap.String("kind", kind), zap.Error(err))
}
}
func (s *NotificationService) render(kind string, recipient, actor *model.User) (string, error) {
data := map[string]any{
"RecipientName": recipient.Name,
"ActorName": actorDisplay(actor),
"ActorHandle": actor.Handle,
"ProfileURL": s.frontendURL + "/u/" + actor.Handle,
}
var tpl *template.Template
switch kind {
case NotifFollowRequest:
tpl = followRequestEmailTpl
case NotifFollowAccepted:
tpl = followAcceptedEmailTpl
default:
tpl = followRequestEmailTpl
}
var buf bytes.Buffer
if err := tpl.Execute(&buf, data); err != nil {
return "", err
}
return buf.String(), nil
}
// actorDisplay prefers the display name, falling back to @handle.
func actorDisplay(u *model.User) string {
if n := strings.TrimSpace(u.Name); n != "" {
return n
}
return "@" + u.Handle
}
// Vaishnava-styled, 17px base to match the feedback emails. Both quote
// the actor and link to their profile (where the recipient can accept a
// pending request).
var followRequestEmailTpl = template.Must(template.New("followRequest").Parse(`
Hare Kṛṣṇa{{if .RecipientName}}, {{.RecipientName}}{{end}} 🙏
{{.ActorName}} (@{{.ActorHandle}})
has requested to follow you on Prabhupāda Says.
You can review and accept or decline the request from their profile:
View request
Your servants,
The Prabhupāda Says team
`))
var followAcceptedEmailTpl = template.Must(template.New("followAccepted").Parse(`
Hare Kṛṣṇa{{if .RecipientName}}, {{.RecipientName}}{{end}} 🙏
{{.ActorName}} (@{{.ActorHandle}})
has accepted your follow request. You're now following them on Prabhupāda Says.
Visit profile
Your servants,
The Prabhupāda Says team
`))